Using the Pin Session command you can pin a particular document to a particular session. Any time you switch to that document, that session will be used.
To pin a session to a document, open the document you wish to pin and press Ctrl+Shift+P and search for Pin Session. A list of sessions will be displayed. Select the session to pin. Any time you switch to that tab, that session will be used. You can unpin a session with Unpin Session.